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What I don't understand is if the problem stated is that one bank of cylinders heat up too much (including cylinder 6), and that temp is higher than the "normal" operating temp of 200F, then how would a thermostat that opens later be of any benefit?
It's been stated dozens of times that the LTT doesn't (shouldn't) reduce the overall operating temp, and if it doesn't do this, then cylinder 6 is still too hot right?
The stated benefit as I understand it is that it's bringing the temp up slower. I guess then the next logical question would be how long SHOULD it take you to bring your engine temp up? When I'm starting out with a cold engine and keeping the revs generally lower than 3k, and never going over 4k, it takes about 15-20 minutes of driving.
I have to admit that after being preoccupied with this for days, and reading everything I can, including the Hartec doc, I'm still skeptical. I don't feel great about throwing in an aftermarket part, following the herd. We all want to avoid engine rebuilds at the end of the day, but this particular change makes me a little uneasy because I still don't understand it.
What I don't understand is if the problem stated is that one bank of cylinders heat up too much (including cylinder 6), and that temp is higher than the "normal" operating temp of 200F, then how would a thermostat that opens later be of any benefit?
It's been stated dozens of times that the LTT doesn't (shouldn't) reduce the overall operating temp, and if it doesn't do this, then cylinder 6 is still too hot right?
The stated benefit as I understand it is that it's bringing the temp up slower. I guess then the next logical question would be how long SHOULD it take you to bring your engine temp up? When I'm starting out with a cold engine and keeping the revs generally lower than 3k, and never going over 4k, it takes about 15-20 minutes of driving.
I have to admit that after being preoccupied with this for days, and reading everything I can, including the Hartec doc, I'm still skeptical. I don't feel great about throwing in an aftermarket part, following the herd. We all want to avoid engine rebuilds at the end of the day, but this particular change makes me a little uneasy because I still don't understand it.
At the end of the day it's up to you .....Keep in mind there are thousands of us to date using the low temp thermostats without any issues . Even with the low temp thermostat my car warms up in approx 15 min or less driving at a constant 2800 rpm or so. The logic behind using the low temp thermostat makes total sense to me and a low temp thermostat option is pretty much offered for most cars including ours by many different part brands so it's not really a revelation to bump down your thermostat for various reasons.
What I don't understand is if the problem stated is that one bank of cylinders heat up too much (including cylinder 6), and that temp is higher than the "normal" operating temp of 200F, then how would a thermostat that opens later be of any benefit?
It's been stated dozens of times that the LTT doesn't (shouldn't) reduce the overall operating temp, and if it doesn't do this, then cylinder 6 is still too hot right?
The stated benefit as I understand it is that it's bringing the temp up slower. I guess then the next logical question would be how long SHOULD it take you to bring your engine temp up? When I'm starting out with a cold engine and keeping the revs generally lower than 3k, and never going over 4k, it takes about 15-20 minutes of driving.
I have to admit that after being preoccupied with this for days, and reading everything I can, including the Hartec doc, I'm still skeptical. I don't feel great about throwing in an aftermarket part, following the herd. We all want to avoid engine rebuilds at the end of the day, but this particular change makes me a little uneasy because I still don't understand it.
I don't think you understand the thermostat difference correctly. The original thermostat is a 180 degree unit. That means it starts opening at 180 and isn't fully open until about 210. The Low Temp Thermostat has a 160 rating - so colder, not hotter - it starts opening at 160 degrees and is fully open by about 190 degrees. This is why it allows the engine to warm up more gradually - because additional coolant is being allowed into the engine earlier spreading the heat around. Think about a pan of boiling water on the stove that's half full. Once it's boiling, if you slowly add in more water, the boiling stops - that's what's happening inside the engine as the LTT thermostat opens sooner and introduces more cooling medium (water) to the system. When both thermostats are fully open the engine temperatures will be identical. The LTT thermostat is fully open 20 degrees sooner than the regular thermostat is which can also prevent the heat soak that takes longer to get rid of.
I don't think you understand the thermostat difference correctly. The original thermostat is a 180 degree unit. That means it starts opening at 180 and isn't fully open until about 210. The Low Temp Thermostat has a 160 rating - so colder, not hotter - it starts opening at 160 degrees and is fully open by about 190 degrees. This is why it allows the engine to warm up more gradually - because additional coolant is being allowed into the engine earlier spreading the heat around. Think about a pan of boiling water on the stove that's half full. Once it's boiling, if you slowly add in more water, the boiling stops - that's what's happening inside the engine as the LTT thermostat opens sooner and introduces more cooling medium (water) to the system. When both thermostats are fully open the engine temperatures will be identical. The LTT thermostat is fully open 20 degrees sooner than the regular thermostat is which can also prevent the heat soak that takes longer to get rid of.
So cylinder 6 will "come to temp" basically a little later? Reading the technical documentation from Hartec it sounds like lower cooling pressure and higher temps overall are the issues?
So cylinder 6 will "come to temp" basically a little later? Reading the technical documentation from Hartec it sounds like lower cooling pressure and higher temps overall are the issues?
Cylinder 6 is last in the coolant system run and why it scores the most - it gets too hot before it starts cooling. With the LTT it will still be last in the string, but it will get cooling sooner so not get as hot.
….It's been stated dozens of times that the LTT doesn't (shouldn't) reduce the overall operating temp, and if it doesn't do this, then cylinder 6 is still too hot right?…..
Understand that the thermostat is the device that controls the “setting point” in the cooling system of the car, that’s mean is the thing that define a what “normal” temperature the engine will run at normal conditions. In any car where the cooling system is properly designed and dimensioned for the application/use, the thermostat will open at at certain defined (factory preset) value -in the case of the LLT is lower so the cooling system will start to flow coolant at that temperature and it will keep the engine at the same temperature (in average) as defined by the thermostat. So yes, with the LTT the engine in normal conditions will work at lower temperature. It probably will take a little bit more time to warm up, specially in cold weather.
In my case I have not changed my thermostat, but I did the third radiator addition and with this particular set up, engine will work at the normal temperature dictated by OE thermostat (approx. 218F) but the cooling system will handle big variations in high temperature loads and cool the engine a lot faster, but always keeping the setting of the system at the temperature set by thermostat. Due to a leak, previous owner changed all components cooling water pump, OE thermostat and cooling reservoir just a couple of thousand miles before my purchase so I did no want to replace TT again until I need to address/service the cooling water pump. So far, even with these crazy high temp over 100F continuously, the car is performing fine, but I completely understand the logic behind use the LTT thermostat. The key should be to use a quality OEM part that won’t fail prematurely (specially in the closed position). I asked my own indie specialist (he do mostly AC 911s) when he installed my center radiator, and he told me to address the TTL the next time when replacing water pump as I don’t track the car.
Understand that the thermostat is the device that controls the “setting point” in the cooling system of the car, that’s mean is the thing that define a what “normal” temperature the engine will run at normal conditions. In any car where the cooling system is properly designed and dimensioned for the application/use, the thermostat will open at at certain defined (factory preset) value -in the case of the LLT is lower so the cooling system will start to flow coolant at that temperature and it will keep the engine at the same temperature (in average) as defined by the thermostat. So yes, with the LTT the engine in normal conditions will work at lower temperature. It probably will take a little bit more time to warm up, specially in cold weather.
In my case I have not changed my thermostat, but I did the third radiator addition and with this particular set up, engine will work at the normal temperature dictated by OE thermostat (approx. 218F) but the cooling system will handle big variations in high temperature loads and cool the engine a lot faster, but always keeping the setting of the system at the temperature set by thermostat. Due to a leak, previous owner changed all components cooling water pump, OE thermostat and cooling reservoir just a couple of thousand miles before my purchase so I did no want to replace TT again until I need to address/service the cooling water pump. So far, even with these crazy high temp over 100F continuously, the car is performing fine, but I completely understand the logic behind use the LTT thermostat. The key should be to use a quality OEM part that won’t fail prematurely (specially in the closed position). I asked my own indie specialist (he do mostly AC 911s) when he installed my center radiator, and he told me to address the TTL the next time when replacing water pump as I don’t track the car.
Is there an OEM part? I was under the impression there wasn't.
I prefer to source this critical part from well known Porsche parts suppliers. For example Pelican Parts has it in both versions. FCP euro, Suncoast Parts, etc. Here is an example. Others can add their own experience with the parts.
So I bought the LN engineering one -- is that ok? In your pic, 83C is the normal high temp one right?
Yes, that's the 180 degree one. Not sure why you'd choose that one but LN Engineering is a proper supplier of the right thermostats and water pumps with composite impellers.
So I bought the LN engineering one -- is that ok? In your pic, 83C is the normal high temp one right?
Yes, 83 C is the one with original Porsche factory spec value set point (full thermostat aperture). The bi-metallic nature of the valve will start to move (opening) at slightly less temperature. You can (if you wish) test the device submerged in water and heating, and measuring water temp with a good thermometer. You will see that thermostat should be fully opened at that temperature value set. Pretty easy. Reverse the process with cold water and it should close.
Never bought parts from LN Engineering but they’re very reputable supply of aftermarket specialty parts for almost exclusively Porsches and they’re well proven the quality for all enthusiasts here, so it should be a high quality part (maybe even better than OE). I follow Charles Navarro (owner) as he is well versed and related with several tech tactics at PCA. So it’s a experience voice there (and here). Maybe other owners already installed the LN LTT and can give more feedback to you.
BTW, I was thinking you were looking for the low temperature one 71C?
Yes, I was looking for the low temp one, but when I asked about an OEM one the guy above posted the regular-temp one. The only reputable one that I found online was the LN one so that's what's been delivered to my mechanic at this point.
09-10-2023, 11:08 PM
